Olfactory navigation and orientation

Abstract

In preceding chapters the role of olfaction in influencing a behavioural response or an ecological relationship has been clear-cut, but in this chapter, which deals with odour cues in navigation and orientation behaviour, there is rather little evidence of an unequivocal nature. This is not because olfaction plays only a minor part in guidance behaviour, but because vertebrate animals utilize all their senses for this important task. If an experimentally blinded animal finds its way back home, the experimenter has not demonstrated that it normally does not use visual cues; rather he has demonstrated that it is able to gather enough information without visual cues. The selective advantage of a multichannel control system seems obvious since the environment through which a migrating animal has to pass is subject to change in both predictable and unpredictable ways. The change from day to night may necessitate in the sense most relied upon shifting from the eyes to, say, the nose, but so may the occurence of an unexpected fog bank. Working, in full integration with one another, the capabilities of each sensory system may be enhanced significantly and this may explain why the experimentally demonstrable sensory capabilities of migrating species sometimes seem inadequate for the task. In the light of the persistent mystery of animal navigation, it is surprising that so little attention has been paid to the part played by olfaction, but perhaps this is a legacy of the anthropocentric nature of the early work on behavioural ecology.